Herald and tribune. [volume] (Jonesborough, Tenn.) 1869-current, 1887-07-21
HEAT IN CIRCULAR saws.
Useful Information on IN Interesting
Mechanical Subject.

Mechanical Subject.
The tendency to heat in circular
saws is the greatest difficulty in their
management Wherever there Is much
friction experienced in one. 1t will get
hot and expand. and in that condition
will not make good lumber, and son1e-
times, indeed. it will buckle, and thus
become materially injured. If the
heating of q saw be tendency to cup.
the side Of the saw which expands
most by heat becomes convex. and If
run too long IL will not return to its
former shape when cooled. but will re-
quire hamnering on the edge to
straighten It, This is job which re-
quires considerable skill, and. besides,
few who use such SAWS have suitable
anvils to straighten them upon. To
such the following will BE- useful
information: Prepare suitable
number of annular papers with
their inside diameter about one inch
less than that of tho hub, and place
them on the shaft adjoining the con-
cave side of the saw Prepare o lot Of
similar papers with their inside diane
ter equal to that of the holo in the
center of tho saw. and their outside
diameter about one inch greater, and
place these on the saw shaft adjoining
the convex side of the saw. A sufli-
cient number of these being so placed
in. they are frightened up in the hub
and the saw is brought up true in the
face. Care must be taken to put in no
more papers than will straightcn the
saw. II is not. however, absolutely
necessary to take the cup out of saw
until il becomes of considerable size,
for a saw will do good work even when
cupped a quarter of an inch; the in
creased difficulty, however. Of manag-
ing it in this condition renders II adj
visible not to work it in such state.
In working cupped saws the teeth
should be made to fill wider gauge
on the convex than on the concavc
side; and If the tendency to heat at the
center continues, II should have more
rake. is cuppcd towards it. The teeth
of-a cupped saw IN ascending. In all
likelihood, will scratch either the face
of the log or the plank, which Is
sufficient reason to at once straighten
by such pressure; they tend to stretch
the saw at the point whercit passes
between them, but the edge Of the saw
is often stretched by cumming ma
chimes II Is seldom necessary to
straighten n buckled saw on an anvil,
especially II only narrow RING, near
the edge Of the saw is stretched, rs 1t
/ may be remedied by cutting through
, it. either by drilling hole Mt the end
n OF each tooth. or filing toward tho Gen.
! ter Of the saw until the stretched part
, is cut through.
t Water is sometimes used to cool q
n saw; II enables the saw to work In q
! smaller kcrf, thus saving power; and
: it also acts as partial lubricator II
4 should be directed In jets on each side
l Of tho saw near the center. Its use,
a however, should bc avoided In cold.
t freezing weather. Allowing the saw
shaft to play cndwisc Is one Of the
most cffectual means Of keeping the
saw cool. When tho timber springs
, against tho saw, tending to heat 1t q,
tho center. the end play Of the shaft
; allows the center of tho saw to yield;
: at the same time the guido pins ut It's
periphery keep it in line, and the fric-
ton is thereby reduced and liability tc
: heat diminished in corresponding dc
gree. --.Amcricdn Cabinet Maker.